from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A plagioclase feldspar, the fifth member of the Albite-Anorthite solid solution series. Bytownite is rare, and normally occurs in small grains in lime-rich igneous rocks. Clear pale yellow crystals have come from Mexico and Oregon.
from The Century Dictionary and Cyclopedia
- n. A kind of feldspar from Bytown (now Ottawa), Canada, intermediate between anorthite and labradorite.
Isolated crystals of bytownite bounded by well-defined faces are unknown.